Structure of a novel class II phospholipase D: Catalytic cleft is modified by a disulphide bridge

• Autor(a) principal: de Giuseppe, Priscila Oliveira
• Data de Publicação: 2011
• Outros Autores: Ullah, Anwar [UNESP], Silva, Dilza Trevisan, Gremski, Luiza Helena, Wille, Ana Carolina Martins, Chaves Moreira, Daniele, Ribeiro, Andrea Senff, Chaim, Olga Meiri, Murakami, Mario Tyago, Veiga, Silvio Sanches, Arni, Raghuvir Krishnaswamy [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.bbrc.2011.05.053; http://hdl.handle.net/11449/72498
• topic: Crystal structure; Loxosceles spider venom; Phospholipase D; phosphodiesterase; phospholipase D; sphingomyelin phosphodiesterase; spider venom; catalysis; crystal structure; disulfide bond; enzyme activity; enzyme binding; molecular weight; nonhuman; priority journal; spider; structure analysis; Amino Acid Sequence; Animals; Catalytic Domain; Crystallography, X-Ray; Cysteine; Molecular Sequence Data; Spider Venoms; Spiders; Araneae; Loxosceles; Loxosceles intermedia; Loxosceles laeta; Thermus

Phospholipases D (PLDs) are principally responsible for the local and systemic effects of Loxosceles envenomation including dermonecrosis and hemolysis. Despite their clinical relevance in loxoscelism, to date, only the SMase I from Loxosceles laeta, a class I member, has been structurally characterized. The crystal structure of a class II member from Loxosceles intermedia venom has been determined at 1.7. Å resolution. Structural comparison to the class I member showed that the presence of an additional disulphide bridge which links the catalytic loop to the flexible loop significantly changes the volume and shape of the catalytic cleft. An examination of the crystal structures of PLD homologues in the presence of low molecular weight compounds at their active sites suggests the existence of a ligand-dependent rotamer conformation of the highly conserved residue Trp230 (equivalent to Trp192 in the glycerophosphodiester phosphodiesterase from Thermus thermophofilus, PDB code: 1VD6) indicating its role in substrate binding in both enzymes. Sequence and structural analyses suggest that the reduced sphingomyelinase activity observed in some class IIb PLDs is probably due to point mutations which lead to a different substrate preference. © 2011 Elsevier Inc.